Surgery

Surgical procedures are recommended for specific patients with advanced Parkinson’s disease who no longer respond to drug treatments. Surgical treatment cannot cure Parkinson disease, but it may help control symptoms such as motor fluctuations and dyskinesia. Pallidotomy and thalamotomy are older procedures that destroy tissue in certain parts of the brain. Deep brain stimulation, the current standard surgical practice for Parkinson’s disease, has largely replaced the older operations.

Deep Brain Stimulation

In deep brain stimulation (DBS), also called neurostimulation, an electric pulse generator controls symptoms. The generator is similar to a heart pacemaker. It sends electrical pulses to specific regions of the brain. Candidates for surgery are generally patients who have responded well to levodopa drug treatment. Patients who have had PD for less than 16 years may experience greater benefit from DBS than patients who have had the disease longer.

Evidence indicates that DBS improves motor function and reduces dyskinesia best when the procedure targets the subthalamic nucleus (STN) of the brain. Many studies demonstrate the effectiveness of STN stimulation. Procedures that target the globus pallidus interna or ventral intermediate nucleus of the thalamus can also sometimes treat rigidity and tremors. However, there is not yet enough evidence to support stimulation of these parts of the brain.

The procedure is performed as follows:

• The surgeon implants a tiny pulse generator near the collarbone, which is connected to four electrodes that have been implanted in the target area in the brain.
• The generator delivers programmed pulses to this area, which the patient can turn on and off using a magnet held over the skin.
• When on, the pulses suppress symptoms. Complications occur in 2 - 4% of operations. The most serious ones are bleeding in the brain and infection. Depression is common.

Pallidotomy and Thalamotomy

Pallidotomy and thalamotomy are surgical procedures that destroy brain tissue in regions of the brain associated with Parkinson’s symptoms such as dyskinesia, rigidity, and tremor. In these procedures, a surgeon drills a small hole in the patient’s skull and inserts an electrode to destroy brain tissue. Pallidotomy targets the global pallidus area. Thalamotomy targets the thalamus. Because these procedures permanently eliminate brain tissue, most experts now recommend deep brain stimulation instead of pallidotomy or thalamotomy.

Surgical complications may include behavioral or personality changes, trouble speaking and swallowing, facial paralysis, and vision problems. Weight gain after surgery is also common.

Stem Cell Implantation

Scientists are investigating whether stem cells may eventually help treat Parkinson disease. Experimental surgery has shown promise using fetal brain cells rich in dopamine implanted in the substantia nigra area of the brain. Because the use of embryonic stem cells is controversial, researchers are studying alternative types of cells, including stem cells from adult brains and cells from human placentas or umbilical cords. Studies are also using gene therapies and other advanced treatments for transplanting dopamine-producing cells or nerve-protecting cells into the brain. All of this research is still in preliminary stages.